A multi-glycomic platform for the analysis of food carbohydrates - Monosaccharide, linkage and polysaccharide (FITDOG) composition analyses of different varieties of apple (figure 5)

Carbohydrates comprise the largest fraction of most diets and exert a profound impact on health. Components such as simple sugars and starch supply energy while indigestible components, deemed dietary fiber, reach the colon to provide food for the tens of trillions of microbes that make up the gut microbiota. The interactions between dietary carbohydrates, our gastrointestinal tracts, the gut microbiome, and host health are dictated by their structures. However, current methods for analysis of food glycans lack the sensitivity, specificity, and throughput needed to quantify and elucidate these myriad structures. This protocol describes a multi-glycomic approach to food carbohydrate analysis where the analyte might be any food item or digested product. The carbohydrates are extracted by… and the resulting samples are subjected to employing rapid-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Quantitative analyses of monosaccharides, glycosidic linkages, polysaccharides, and alcohol soluble carbohydrates are performed in 96-well plate format to reduce the biomass of sample required and enhance throughput. Detailed stepwise processes for sample preparation, LC-MS/MS, and data analysis are provided. We illustrate the application of the protocol to a diverse set of foods as well as different apple cultivars and various fermented foods. Furthermore, we show the utility of these methods in elucidating glycan-microbe interactions in germ-free and colonized mice. These methods provide a framework for elucidating relationships between dietary fiber, the gut microbiome, and human physiology. These structures will further guide nutritional and clinical feeding studies that enhance our understanding of the role of diet in nutrition and health.